Pressure responsive apparatus including valve actuating means

ABSTRACT

A needle valve actuator is disposed in the port fitting of a pressure switch so that upon placement of the switch on a coupling containing the needle valve, the valve is automatically actuated when the switch is mounted thereon. The coupling and needle valve is located in a conduit of a refrigeration or air conditioning system to provide access to the refrigerant in the system, for instance to test the pressure level at that particular point or to recharge the system. After this is accomplished the pressure switch is placed on the nipple of the coupling and screwed into place to perform its protective or indicative function.

United States Patent [191 [111 3,864,537

Fiore Feb. 4, 1975 PRESSURE RESPONSIVE APPARATUS INCLUDING VALVEACTUATING MEANS Inventor: Peter O. Fiore, Cumberland, R.l.

Assignee: Texas Instruments Incorporated,

Dallas, Tex.

Filed: Apr. 16, 1973 Appl. No.: 351,751

References Cited UNITED STATES PATENTS 5/1964 Griffith 200/83 S l/1967Dalton ZOO/61.25 X 6/1971 Halpert et al 200/83 S 7/1971 Ritchie 251/1496Primary Examiner-Robert K. Schaefer Assistant ExaminerGerald P. TolinAttorney, Agent, or Firm-John A. Haug; James P. McAndrews [57] ABSTRACTA needle valve actuator is disposed in the port fitting of a pressureswitch so that upon placement ofthe switch on a coupling containing theneedle valve, the valve is automatically actuated when the switch ismounted thereon. The coupling and needle valve is located in a conduitof a refrigeration or air conditioning system to provide access to therefrigerant in the system, for instance to test the pressure level atthat particular point or to recharge the system. After this isaccomplished the pressure switch is placed on the nipple of the couplingand screwed into place to perform its protective or indicative function.

6 Claims, 7 Drawing Figures PATEIHEU FEB 41975 r 7 sum 10F 5 3 864 53CONDENSER 81-. HIGH PR L/M/T SM)? 6 COMPRESSOR 7 LOW PR L/M/TJMIZI/ 144POEM 70/? SHEET 5 OF 5 PATENTED FEB 75 PRESSURE RESPONSIVE APPARATUSINCLUDING VALVE ACTUATING MEANS BACKGROUND OF THE INVENTION sponsiveswitch having mounted therein valve actuating means.

Incertain systems, such as refrigerant or air conditioning, it isdesirable to locate pressure switches at one or more locations toprovide protection or indication of a particular pressure condition. Forinstance in an air conditioning system it may be desirable to place ahigh limit pressure switch on the high pressure side of a compressor toprevent excessive pressure build up by the compressor. It is alsodesirable in such systems to provide one or more places of access intothe system conduits so that the refrigerant can be recharged or thepressure level can be tested. It is frequently desirable to place thepressure switches at one or more of these places of access. Essentiallya place of access comprises a coupling mounted on the refrigerantconduit with a needle valve disposed in the coupling. In order tooperatively mount the pressure switch, means must be provided to actuatethe valve so that the system pressure can reach the pressure responsivediaphragm of the switch.

SUMMARY OF THE INVENTION Briefly in accordcnce with this invention,valve actuation is accomplished by employing a port fitting having firstand second threaded bores communicating with each other and with thepressure chamber of the switch. The first bore receives the couplingcontaining the needle valve while an actuator element is received in thesecond bore. The actuator element is formed of material having a firsthardness harder than a second hardness of the port fittingand is a platelike element forced into the first thread of the second bore nearest thefirst bore which securely positions the element at a selected referencepoint. Preferably a bored calibration screw is also received in thesecond bore to enable adjustment of the pressure switch. The element isprovided with a stem received in the bore of the screw to maintain theelement along the bore axis and prevent twisting thereof and is movablerelative to the screw so that the screw can be moved without affectingthe position of the element. The screw is preferably adjusted beforeinstallation of the actuating element. As the port fitting is insertedinto the coupling and screwed into place the actuator contacts theneedle valve and moves it from the valve seat.

Thus it is an object of the invention to provide means to actuate anaccess valve upon mounting of a pressure switch. Another object is theprovision of such means which can be used with a pressure switch havinga calibration screw in its ingress without adding to the volume of thefitting and which allows adjusting movement of the screw.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, in whichthe preferred embodiment of the invention is illustrated:

FIG. 1 is a schematic diagram of a system in which the invention can beemployed;

FIG. 2 is a cross sectional view, partly broken away of a pressureswitch provided with means to actuate an access valve, the access valvebeing located in a coupling with the pressure switch partly securedthereto;

FIG. 2a is a partial section of FIG. 2 showing in detail the mounting ofthe valve actuator element shown with the adjusting screw removed;

FIG. 3 is similar to FIG. 2 but with the pressure switch broken away andshown with the coupling seated in a seating portion of the pressureswitch port with the access valve in the actuated position;

FIG. 4 is similar to FIG. 3 but with a calibrating screw shown in adifferent position relative to FIG. 3;

FIG. 5 is a perspective view of an actuator element used in the FIG. 2-4device; and

FIG. 6 is a top plan view of the FIG. 2-4 device.

Dimensions of certain of the parts as shown in the drawings may havebeen modified to illustrate the invention with more clarity.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings,FIG. 1 shows'a schematic diagram of an air cooling system comprising acondenser 1 connected to an evaporator 2 through conduit 3 withexpansion valve 4 located intermediate condenser l and evaporator 2.Conduit 5 couples evaporator 2 back to condenser 1 through a compressor6. A low pressure limit switch may be placed on the suction side ofcompressor 6 while a high pressure limit switch may be placed betweencompressor 6 and condenser l.

By way of example forced air passes over evaporator 2 which extractsheat therefrom, which heat is absorbed by refrigerant liquid containedin the evaporator as heat of vaporization changing the liquid to avapor. The vapor is drawn by suction from evaporator 2 by compressor 6which increases the pressure of the vapor and discharges the vapor fromthe compressor at a saturation temperature sufficiently high that thevapor can be condensed in condenser 1 across which forced cooling airpasses which absorbs the heat of vaporization, condensing the vapor backto a liquid. The liquid refrigerant then is passed through expansionvalve 4 to the lower pressure of the evaporator.

Pressure switch 7 may be placed on the suction side of compressor 6 toindicate entry of liquid to the compressor while pressure switch 8 maybe placed on the high pressure side of compressor 6 to guard againstexcessive pressure build up by the compressor. The construction of aswitch useful for pressure switches 7 and 8 is shown in FIG. 2 whereinswitch 10 comprises a cylindrical cup-shaped member 12 formed of aconventional molded electrically insulative phenolic material and formedwith apertures l4, 16 for reception therein of support member 18 andstationary contact 20 respectively. Movable contact arm 22 ofelectrically conductive material having good spring characteristics,such as beryllium nickel, is cantilever mounted to support member 18 asby riveting at 24. Arm 22 is formed with a dimple 26 to facilitatetransfer of motion from motion transfer pin 28 slidably mounted inalignment with dimple 26. Arm 22 mounts at its free end movable contact30 and is adapted to move into and out of engagement with a transverselyextending section 'of contact 20. To improve electrical conductivitywhile minimizing additional expense, stationary contact 20, which alsoserves as part of the terminal structure, is preferably provided with alayer 32 of highly conductive material, such as a silver alloy. Theouter ends of support 18 and stationarycontact 20 pass through apertures34, 36 of terminal member 38, 40 respectively, and are headed over tosecurely lock the contactassembly in the housing and to provideelectrical connection to the switch via respective leads L1, L2electrically connected thereto.

A disc 50, generally plate-shaped of electrically insulative material,is formed with an annular seating groove 52 about its periphery and isreceived in the distal portion of wall 54 of base 12. Disc 50 slidablymounts in a centrally located bore 56 pin 28, also of electricallyinsulative material such as a ceramic or glass material, and isolatesthe electrical switch from the diaphragm area.

Tubular member 66, which may be formed of a conventional metallicmaterial, is provided with a radially outwardly extending flange 68 andis placed over the distal wall 54 of base 12 and attached thereto, as bycrimping. A small flange 72 is provided on distal wall 54 to permitlocking of the tubular member 66 to base 12. Mounted on flange 68arecalibration-stop member 74, imperforate circular diaphragm member 76and cover 78, all hermetically secured at their periphery, as by weldingat 80. Cover 78 is dished out at 82 to provide a cavity 84 sealed bydiaphragm 76 and provided with bore 86 for reception therein of a portfitting 88 which is hermetically attached thereto. Port fitting 88permits attachment to conduit as will be explained in greater detailbelow.

Diaphragm 76 is formed into a snap-acting disc by means known in theart. During operation of the device diaphragm 76 snaps from the convexposition shown in FIG. 2 looking from the pressure receiving side to anopposite concave curvature when a predetermined amount of pressure isintroduced into chamber 84 through port fitting 88. The diaphragm willsnap back to its original position when the pressure decreases apredetermined amount.

Cap 90 has an annular seat 92 which receives the outer peripheralportion of cover 78, diaphragm 76, calibration stop member 74 andtubular member 66. Cap 90 is provided with apertures 94, 96 forreception therethrough of insulated wires L1, L2 respectively.

Cap 90 is then back filled with suitable electrically in- I sulativematerial such as potting material 98.

The difference in pressure between that amount at which the diaphragmsnaps in a first direction and that amount at which the diaphragm willreturn to its original position is controllable by calibrating thedevice by deforming the calibration stop member 74 explained in detailand to which reference may be had in US. Pat. No. 3,584,168 issued June8, 1971 and assigned to the assignee of the instant invention.

Port fitting 88 is provided with a first threaded bore 100 incommunication with a second smaller threaded bore 102, the two boresbeing joined by a conical seat portion 104 and communicating with cavity84 for reception of pressure (or vacuum). Port fitting 88 is pro videdwith boss 106 which is received in mating aperture 86 in cover 78.Adjusting screw 108 is disposed in bore 102 and it also has alongitudinally extending bore 110 and a spring seat 112 for reception ofspring 114 which extends from the spring seat 112 to diaphragm 76.Spring 114 and adjusting screw 108 are optional and may be used if itis' desirable to selectively narrow the pressure differential of thediaphragm, however, use of the screw is preferred to facilitate mountingof valve actuating element 116.

Also disposed in the bore 102 of the port fitting is a plate likeactuator element 116 formed of material such as stainless steel having afirst hardness. Element 116 has transversely extending tabs 118intermediate an actuating surface 120 and a longitudinally extendingstem 122. Port fitting 88 is formed of material such as bronze or brasshaving a second hardness softer than that of element 116. As best seenin FIG. 2a the element is inserted into bore 102 with tabs 118 forcedthrough the first thread of the bore to be securely fixed in the portfitting with the first thread also serving as a reference point forlocating actuating surface 120. Stern 122 extends into bore 110 ofadjusting screw 108 which maintains the element on the longitudinal axisof bore 102 and prevents any tendency of the element to twist. Screw 108is preferably adjusted prior to the installation of actuator element116. Stem 122 is sufficiently loosein bore 110 however to permitrelative movement between screw 108 and stem 122.

Coupling 126 having opposite threaded ends 128, mounts therein needlevalve 132. End 128 is received in conduit 5 with valve 132 providingaccess to the system refrigerant. Port fitting 88 is screwed onto end ornipple 130 untilbeveled portion 134 on the distal end of the nipplebottoms against conical seat 104. As seen in FIG. 2 port fitting 88 hasbeen screwed only part way onto nipple 130, needle 136 of valve 132being spaced a short distance from actuating surface 120 of element 116and beveled surface 134 of nipple I30 spaced a slightly greater distancefrom conical seat 104. Thus continued clockwise rotation of port fittingwill cause needle 136 to contact surface 120 and be moved upwardly offits valve seat allowing pressure from conduit 5 to enter cavity 4 ofswitch 10. As seen in FIG. 6 element 116 occupies only a portion of thecross sectional area of bore 110 allowing pressure received throughvalve 132 to pass through bore 110. Port fitting 88 is rotated untilfinally conical seat 104 contacts beveled surface 134 of nipple 130preventing further rotation. This position is illustrated in FIG. 3.FIG. 4 illustrates the adjusting screw moved to increase spring pressureon diaphragm 76 without affecting the position of actuating element 116.

Thus it will be seen that switch 10 may be removed at will to provideaccess to conduit 5 should testing or recharging of the refrigerant bedesired. Switch 10 may then be remounted on nipple 130 automaticallyactuating valve 132 as port fitting 88 is screwed into place yet withoutaffecting the ability to calibrate switch 10 in any way.

Although the invention has been described with re,- spect to specificpreferred embodiments thereof, many variations and modifications willimmediately become apparent to those skilled in the art. It is thereforethe intention that the appended claims be interpreted as broadly aspossible in view of the prior art to include all such variations andmodifications.

I claim:

1. In combination with a pressure responsive switch having a housing anda pressure responsive diaphragm mounted in the housing and movable froma first configuration to a second opposite configuration the motion fromthe diaphragm transmitted to a movable electric contact which is adaptedto move into and out of engagement with a stationary contact uponmovement of the diaphragm from one configuration to the oppositeconfiguration and a port fitting for reception of pressure to a surfaceof the diaphragm, the port fitting provided with a threaded bore, abored adjustive screw disposed in the threaded bore and a springextending from the screw to the pressure responsive diaphragm wherebythe bias of the spring can be adjusted by movement of the adjustingscrew, a coupling containing an axially actuatable valve and on whichthe port fitting is mounted, the improvement which comprises anactuating element positioned in the port fitting in alignment with theaxially actuatable valve whereby the valve is actuated upon mounting ofthe port fitting on the coupling, the actuator element being formed ofmaterial having a first hardness and the port fitting is formed ofmaterial having a second hardness softer than the said first hardnessand the element is pressed into and cuts threads of the threaded bore ofthe port fitting to lock it in place, the actuator element having a stemdepending therefrom, the stem extends into the bore of the adjustingscrew and fits loosely enough to permit relative movement between screwand stem and tightly enough to prevent any tendency of the actuatingelement to twist.

2. The combination according to claim 1 in which the actuator elementhas transversely extending tabs which are pressed into the said threads.

3. The combination according to claim 1 in which the port fitting isprovided with a second threaded bore the bores in communication witheach other, the first bore having a larger diameter than the secondbore, the two bores joined by a beveled seating portion, the first boreadapted to receive the threaded end of a coupling, the coupling adaptedto seat against the seating portion, the actuator element formed withtwo transversely extending tabs and formed of material harder than thematerial of the port fitting, the tabs pressed into the first thread ofthe second bore nearest the beveled seating portion which serves as areference point for the position of the actuator element.

4. The combination according to claim 3 in which the actuator elementhas a depending stem, a bored adjusting screw is disposed in the secondthreaded bore with the stem extending into the bore.

5. The combination according to claim 4 in which the adjusting screw ismovable relative to the actuating element.

6. A switch assembly according to claim 1 in which the coupling has athreaded nipple receivable in the first threaded bore and having adistal portion engageable with the seating portion, an axially extendingneedle valve is disposed in the nipple and is adapted to be contacted byan actuating surface of the actuating valve as the port fitting isthreaded onto the nipple before the distal portion of the nipple engagesthe seating portion.

1. In combination with a pressure responsive switch having a housing anda pressure responsive diaphragm mounted in the housing and movable froma first configuration to a second opposite configuration the motion fromthe diaphragm transmitted to a movable electric contact which is adaptedto move into and out of engagement with a stationary contact uponmovement of the diaphragm from one configuration to the oppositeconfiguration and a port fitting for reception of pressure to a surfaceof the diaphragm, the port fitting provided with a threaded bore, abored adjustive screw disposed in the threaded bore and a springextending from the screw to the pressure responsive diaphragm wherebythe bias of the spring can be adjusted by movement of the adjustingscrew, a coupling containing an axially actuatable valve and on whichthe port fitting is mounted, the improvement which comprises anactuating element positioned in the port fitting in alignment with theaxially actuatable valve whereby the valve is actuated upon mounting ofthe port fitting on the coupling, the actuator element being formed ofmaterial having a first hardness and the port fitting is formed ofmaterial having a second hardness softer than the said first hardnessand the element is pressed into and cuts threads of the threaded bore ofthe port fitting to lock it in place, the actuator element having a stemdepending therefrom, the stem extends into the bore of the adjustingscrew and fits loosely enough to permit relative movement between screwand stem and tightly enough to prevent any tendency of the actuatingelement to twist.
 2. The combination according to claim 1 in which theactuator element has transversely extending tabs which are pressed intothe said threads.
 3. The combination according to claim 1 in which theport fitting is provided with a second threaded bore the bores incommunication with each other, the first bore having a larger diameterthan the second bore, the two bores joined by a beveled seating portion,the first bore adapted to receive the threaded end of a coupling, thecoupling adapted to seat against the seating portion, the actuatorelement formed with two transversely extending tabs and formed ofmaterial harder than the material of the port fitting, the tabs pressedinto the first thread of the second bore nearest the beveled seatingportion which serves as a reference point for the position of theactuator element.
 4. The combination according to claim 3 in which theactuator element has a depending stem, a bored adjusting screw isdisposed in the second threaded bore with the stem extending into thebore.
 5. The combination according to claim 4 in which the adjustingscrew is movable relative to the actuating element.
 6. A switch assemblyaccording to claim 1 in which the coupling has a threaded nipplereceivable in the first threaded bore and having a distal portionengageable with the seating portion, an axially extending needle valveis disposed in the nipple and is adapted to be contacted by an actuatingsurface of the actuating valve as the port fitting is threaded onto thenipple before the distal portion of the nipple engages the seatingportion.